Sz cabling device for communication cables

ABSTRACT

Cabling device has means for twisting strand elements into respective twisted units having a twist direction which varies from section to section thereof (alternate-reverse twist), and means for simultaneously twisting a plurality of such twisted units into a twisted group also having a twist direction varying from section to section thereof. This two-stage cabling operation is effected by the aid of accumulators. Between the two twisting stages, i.e. the twisted unit-forming means and the twisted group forming means, at least one pulling device is disposed, the pulling device being revolvable about an axis corresponding to the axis of the twist of the twisted units and the twisted group.

United States Paten r191 Vogelsberg [451 Jan. 1, 1974 1 sz CABLING DEVICE FOR COMMUNICATION CABLES [75] Inventor:

[73] Assignee: Siemens Aktiengesell s l alt, Berlin and Muiiicli ffj miiny [22] Filed: Jan. 24,. 1972' [2]] Appl. No.2 220,191

Dieter Vogelsberg, Berlin, Germany [30] Foreign ApplicationPriority Data 3,412,544 11/1968 Sugi et al 57/34 AT 3,48l,l27 l2/l969 Vogelsherg 57/34 AT 3,49l,525 l/l970 Sugi 57/34 AT Primary Examiner-John Petrakes Attorney-Arthur E. Wilfond et al.

[ 57] ABSTRACT Cabling device has means for twisting strand elements into respective twisted units having a twist direction which varies from section to section thereof (alternate-reverse twist), and means for simultaneously twisting a plurality of such twisted units into a twisted group also having a twist direction varying from section to section thereof. This two-stage cabling operation is effected by the aid of accumulators. Between the two twisting stages, i.e. the twisted unit-forming means and the twisted group forming means, at least one pulling device is disposed, the pulling device being revolvable about an axis corresponding to the axis of the twist of the twisted units and the twisted group.

7 Claims, 2 Drawing Figures SZ CABLING DEVICE FOR COMMUNICATION CABLES This invention relates to cabling or twisting of communication cables. For this purpose, methods and devices have been developed recently by which cable elements are twisted alternately with a left-hand twist (S- twist) and a right-hand twist (Z-twist) along successive portions of their length. All twists of this kind, which are referred to as SZ-twists, have the advantage that the strand elements to be twisted into a cable unit can run off stationary feed frames and that further processing of the SZ-twisted strand elements forming the twisted cable units can ensue in the same operation.

Generally, revolving twisting devices, which include an accumulator, serve for effecting the SZ-twisting or cabling. The accumulators can revolve with a rotary speed or rotary direction that varies from section to section, while the run-through speed of the strand elements is constant (U. S. Pat. No. 3,169,360). The accumulators are also revolvable at constant rotary speed and rotary direction, while the run-through speed of the cable elements is varied from section to section (French Pat. No. 1,468,382). A further possibility is to increase and decrease the accumulator content alternatingly, while the rotary motion of the accumulator remains the same (German Pat. No. 1,665,831). Finally, it is also 'known to operate with stationary accumulators around which twisting or cabling yokes re- Volvo-(German Pat. No. 1,665,536).

In 82 twisting or cabling, two successive and formerly separately executed twisting processes, for instance for twisting conductors to form quads and twisting several quads to form a basic group,are combined in a single operation. The second twisting operation can be effected by means of a rotary pulling and takeup device. The second twisting operation is often also an S2 twisting operation, however, in order to facilitate operating with a stationary pulling and take-up device.

If the cable elements are pulled through two 82 twisting or cabling devices arranged in tandem, in which the respective cable elements pass in several turns through at least one accumulator, considerable tensile forces are exerted on the cable elements. To reduce these tensile forces, it has been known heretofore to provide, between the SZ twisting device of the first twisting stage and the S2 twisting device of the second twisting stage, one or more additional stationary pulling devices by which each twisted cable unit produced in the first twisting stage is pulled off separately. These additional pulling devices relieve the pulling device proper which is located behind or downstream of the second twisting stage in the travel direction of the cable (Wire and Wire Products, January 1967, pages 90 to 97, pages 159 and 160). The danger exists, however, that the S2 twisted cable units formed of the cable or strand elements may untwist at the reversal points of the direction of the twist as the 82 cable units run through the additional pulling devices. This applies particularly to twisting processes in which the cable or strand elements are not provided with an adhesive prior to twist- It is an object of the invention, in multi-stage SZ twisting or-cabling operations, to reduce the tensile forces exerted on the cable or strand elements without impairing the twisting of the cable elements.

With the foregoing and other objects in view, there is provided, in accordance with the invention, cabling device comprising a first twisting stage for twisting strand elements into respective twisted units having a twist direction varying from section to section thereof, a second twisting stage for simultaneously twisting a plurality of the twisted units into a twisted group also having a twist direction varying from section to section thereof, the first and the second twisting stages each including an accumulator, and at least one pulling device disposed between the first and the second twisting stages and revolvable about the axis of twist of the twisted group.

When passing through the cabling device of the invention which is provided with only the one pulling device common to all of the twisted units, the twisted units produced from the strand elements in the first twisting stage are twisted together by means of the pull ing device revolving about the axis of twist of the group twisting device. The twisted units therefore pass through the pulling device in a twisted-together condition. Consequently, untwisting of the twisted units at the reversal points of the direction of twist is prevented in the region of the pulling device disposed ahead or upstream of the group twisting device in direction of cable travel.

The use of revolving pulling devices in the twisting of strand or cable elements for communication cables has been known heretofore. For example, in the twisting of conductors or cable elements to form quads by means of a twisting yoke rotating around the take-up drum, a rotating caterpillar pulling device can be suitable for the purpose ofeffecting a pretwisting operation for the purpose of symmetrizing the path of the conductor or cable element (German Published Pat. application No. 1,084,796). In another heretofore known twisting machine, the twisting is accomplished with the aid of a revolving pulling and take-up device wherein the pulling stage of the device is constructed as a sheave (German Published Pat. application 1,510,088). In accordance with the invention, however, it is not merely that a revolving pulling device is employed therein but, moreover, that it is employed in a two-state SZ twisting process, ahead or upstream of the second of the two twisting stages.

In the device constructed according to the invention with a pulling device in common for all of the cable units, the 82 cable units which are mutually twisted together as they enter into the pulling device, are twistreversed when leaving the pulling device, if the latter revolves independently of the next following downstream group twisting device. Therefore, in accordance with another feature of the invention, the pulling device is revolvable at the same speed and in the same rotary direction as the group twisting device, or with the entry or inlet part of the group twisting device. A twist reversal of the mutually twisted-together 52 cable units as they enter the group twisting device is thereby prevented.

In accordance with a further embodiment of the invention, there is provided a cabling device having a group twisting device that is revolvable at constant speed and is equipped with rollers or sheaves for guiding the strand or cable elements, the first sheave over which the strand or cable units pass being constructed as a pulling sheave. In this embodiment, accordingly, the revolving pulling device and the revolving group twisting device are structurally combined one with the other.

As mentioned hereinbefore, instead of one common pulling device for all strand or cable units, there can be provided, further in accordance with the invention, one revolving pulling device, respectively, for each of the strand or cable units twisted by the twisting devices. Thereby, the withdrawal or pulling of each twisted or cable unit for itself is effected in the conventional manner customary for a stationary pulling device. By suitable selection of the rotary speeds and rotational directions of the pulling devices, which revolve about the axis of twist of the respective twisting device, it is possible to assure that the pulling devices are not traversible by reversal points of the twist direction of the twisted or cable units, but rather only by twist change points. For instance, each pulling device can revolve with the same speed and direction of rotation as the respective twisting device associated therewith or as the output or outlet part of that twisting device. In this case, it is advantageous and in accordance with the invention, to connect mechanically each of the revolving pulling devices with the respective twisting device associated therewith. If, in this case, the twisting devices contain revolving rollers or sheaves for guiding the strand or cable elements, in accordance with an additional feature of the invention, the last sheave over which the strand or cable elements pass, is constructed as a pulling sheave.

Other features which are considered as characteristic for the invention are set forth in the appended claims.

Although the invention is illustrated and described herein as SZ cabling device for communication cables, it is nevertheless not intended to be limited to the details shown, since various modifications may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The invention, however, together with additional objects and advantages thereof will be best understood from the following description when read in connection with the accompanying drawing, in which:

FIGS. 1 and 2 are diagrammatic views of different embodiments of the cabling device of the invention.

Referring now to the drawing and first, particularly to FIG. 1 thereof, there is shown an embodiment of the cabling device of the invention which serves for twisting 20 conductors or cable elements 1 ofa communication cable to form a basic cable group 3. In this process,

four conductors or cable elements I are each initially twisted by means of parallel-operating twisting devices 5 to form five quads 2 and, subsequently, in the same operation, the quads 2 are twisted together by means of the group-twisting device 6, to form a basic cable group 3. The twisting devices 5 and the group twisting device 6 are conventional 82 twisting machines, each of which includes one or two accumulators and twists the cable elements 1 or quads 2, respectively, to form respective twisted or cable units or a twisted or cable group having a direction of twist that is reversed successively from section to section thereof.

The pulling of the conductors or cable elements 1 through the twisting devices 5 is accomplished by means of a withdrawing or pulling device 7 which revolves in the direction of the arrow A around the axis of twist and which is located ahead or upstream of the group twisting devices 6 in the travel direction of the cable. With the aid of the stationary take-up device 8, the conductors or cable elements 1, which are twisted to form the basic cable group 3, are pulled through the group twisting device 6. With respect thereto, the takeup drum 9 is driven with constant torque. The pulling device 7, which rotates in the direction of the arrow B, thus establishes the pulling speed of the conductors or cable elements 1 and thereby the through-pulling speed of the conductors or cable elements 1, the quads 2 and the basic cable group 3 through the entire machine.

The pulling device 7, which revolves in the direction of the arrow A with constant speed and constant rotary direction, is a rotating pulling sheave to which the quads 2 are fed through the intermediary of a deflecting roller 10 and are led off by a deflecting roller 11 after being looped several times around the pulling sheave 7. The pulling device 7 can include, in lieu of a revolving pulling sheave, also a revolving conventional double roller device, or a revolving caterpillar-type pulling device.

The quads 2 are provisionally mutually twisted together to form a cable group 3 in the twisting nipple 12 by the revolving pulling device 7. When the cable group 3 enters or runs into the cable group twisting device 6, a twist reversal of the cable group 2 takes place if the group twisting device 6 or its input or inlet part revolves with a speed and/or rotary direction other than that of the pulling device 7.

Twist reversal of the cable group 3 when it leaves the pulling device 7 can be avoided if the group twisting device 6 is an SZ twisting machine which revolves with constant speed and rotary direction. This applied particularly to the case of S2 twisting machines which include one or two accumulators, the accumulated contents of which are alternatingly increased and decreased by sections. Such an embodiment of the invention is shown in FIG. 2.

The cable group twisting device of the embodiment of FIG. 2 is a conventional double accumulator device (German Published Pat. application No. 1,665,831 wherein each of the two accumulators 15 and 16 is constructed as a sheave or roller accumulator. By means of this accumulator assembly, the quads 2, which are united in the twisting nipple 17, are SZ-twisted to form the basic cable group 3.

The accumulators l5 and 16 revolve with constant speed and in opposite rotary direction as represented by the respective arrows A and C in FIG. 2. The quads 2 are fed to the respective accumulators 15 and 16 over respective deflecting sheaves or rollers 18 and 19 which revolve together with the respective accumulators about the axis of twist and are led off from the respective accumulators over a corresponding deflecting roller or sheave 20 and 21, respectively. The deflecting sheave 18 over which the quads 2 are fed to the accumulator 15 is constructed as a pulling sheave. In order to prevent slippage, the quads 2 are looped around the pulling sheave 18 several times. The latter is driven with constant speed and therefore establishes or determines the pulling speed of the entire twisting machine.

The take-up device 8 located behind or downstream of the cable group twisting device 16 in FIG. 2 includes a take-up drum 9 driven with constant torque in a manner similar to that of the take-up device 8 shown in FIG. 1.

I Claim:

1. Cabling device comprising a first twisting stage for twisting strand elements into respective twisted units having a twist direction varying from section to section thereof, a second twisting stage for simultaneously twisting a plurality of said twisted units into a twisted group also having a twist direction varying from section to section thereof, said first and said second twisting stages each including an accumulator and a pulling device disposed between said flrst and said second twisting stages and revolvable about the axis of twist of said twisted group.

2. Cabling device according to claim 1 wherein said pulling device is common to all of the twisted units and is revolvable at the same speed and in the same rotary direction as said second twisting stage.

3. Cabling device according to claim 2 wherein said second twisting stage includes separately revolvable input and output parts of the twisted units being twisted into a twisted group, said pulling device being revolvable at the same speed and in the same rotary direction as said input part of said second twisting stage.

4. Cabling device according to claim 3 wherein said pulling device is firmly connected mechanically to said input part of said second twisting stage.

5. Cabling device according to claim 2 wherein said pulling device is firmly connected mechanically to said second twisting stage.

6. Cabling device according to claim 1 wherein said second twisting stage is revolvable at constant rotary speed and comprises a plurality of rollers for guiding the twisted units in a given travel direction therethrough, said pulling device being a roller located upstream of and being revolvable with said plurality of guiding rollers, said pulling device roller being in the form of a pulling sheave.

7. Cabling device according to claim 1 including a take-up drum located downstream of said second twisting stage and being adapted to be wound up by the twisted group twisted from the plurality of twisted units, said take-up drum being rotatable with constant torque, and said pulling device located upstream of said second twisting stage being operable so as to determine the speed at which the strand elements are pulled through the cabling device. 

1. Cabling device comprising a first twisting stage for twisting strand elements into respective twisted units having a twist direction varying from section to section thereof, a second twisting stage for simultaneously twisting a plurality of said twisted units into a twisted group also having a twist direction varying from section to section thereof, said first and said second twisting stages each including an accumulator and a pulling device disposed between said first and said second twisting stages and revolvable about the axis of twist of said twisted group.
 2. Cabling device according to claim 1 wherein said pulling device is common to all of the twisted units and is revolvable at the same speed and in the same rotary direction as said second twisting stage.
 3. Cabling device according to claim 2 whereIn said second twisting stage includes separately revolvable input and output parts of the twisted units being twisted into a twisted group, said pulling device being revolvable at the same speed and in the same rotary direction as said input part of said second twisting stage.
 4. Cabling device according to claim 3 wherein said pulling device is firmly connected mechanically to said input part of said second twisting stage.
 5. Cabling device according to claim 2 wherein said pulling device is firmly connected mechanically to said second twisting stage.
 6. Cabling device according to claim 1 wherein said second twisting stage is revolvable at constant rotary speed and comprises a plurality of rollers for guiding the twisted units in a given travel direction therethrough, said pulling device being a roller located upstream of and being revolvable with said plurality of guiding rollers, said pulling device roller being in the form of a pulling sheave.
 7. Cabling device according to claim 1 including a take-up drum located downstream of said second twisting stage and being adapted to be wound by the twisted group twisted from the plurality of twisted units, said take-up drum being rotatable with constant torque, and said pulling device located upstream of said second twisting stage being operable so as to determine the speed at which the strand elements are pulled through the cabling device. 